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A family go into a shop, they buy three sandwiches and two packets of crisps. It costs them £9. Another family buy five sandwiches and six packets of crisps. It costs them £19. How much does two sandwiches and five packets of crisps cost?

We will call sandwiches S and packets of crisps C. These are the 'unknowns'. From the information we can write down two equations. Equation 1: 3S + 2C = 9 and Equation 2: 5S + 6C = 19. We need two equations ...
SS
Answered by Sharmi S. • Maths tutor
3358 Views

A ball, dropped vertically, falls d metres in t seconds. d is directly proportional to the square of t. The ball drops 45 metres in the first 3 seconds. How far does the ball drop in the next 7 seconds?

If d is directly proportional to the square of t, we write this as d= kt 2 , where k = the proportionality constant which we must find. Substitute in the values given in the question into our equation to get...
KL
Answered by Katie L. • Maths tutor
22610 Views

The perimeter of an isosceles triangle is 16cm. The length of the base of the triangle is x+4 and that of the other two sides is x+3. Find the area of the triangle

16=2(x+3)+(x+4)16=2x+6+x+46=3xx=2 - Therefore the base has length 6 a=6y/2 - where y is the perpendicular heighty^2=5^2-3^2y^2=25-9y^2=16y=4 Therefore a=(6*4)/2 a=12 cm^2
PF
Answered by Philip F. • Maths tutor
4427 Views

Find the coordinates and the point of intersection between the lines 8x + 7y = 11 and y = 5x + 2

Substitute y = 5x + 2 into 8x + 7y = 11 to get, 8x + 7(5x + 2) = 11This simplifies down to 8x + 35x + 14 = 11And further simplifies to 43x = -3 giving the solution x = -3/43Substituting the x solution back i...
AR
Answered by Adam R. • Maths tutor
3103 Views

a)By completing the square, prove the quadratic formula starting from ax^2+bx+c=0, b) hence, or otherwise solve 3x^2 + 7x -2= 9, to 3s.f.

a)starting from ax 2 +bx+c=0, divide through by a, x 2 +(b/a)x+c/a=0, complete the square (x+(b/2a)) 2 -(b/2a) 2 +c/a=0, expand (x+(b/2a)) 2 -(b 2 /4a 2 )+c/a=0, Combine fractions and rearrange,(x+(b/2a)) 2 ...
YH
Answered by Yusuf H. • Maths tutor
3903 Views